Our cat Sugi is terrified - terrified - of headgear which changes the outline of people's heads. He's okay it's like a wool cap or something but if it's got a wide brim or worse yet sticks up somehow, he loses it and runs away. We discovered this one year when it was Christmas and we were all wearing our antlers, and he walked into the room, stared in horror usually reserved for Elder Gods, and then absolutely belted out of there.